Whether essaying a dramatic role on stage, singing and dancing on television, or cutting up in a movie comedy, Duilio Del Prete knew how to please an audience and as a result was one of Italy's most popular stars. His most famous film appearance was in Mario Monicelli's comedy Amici Miei (1975). Other popular films include Vogliamo I Colonelli (1973), Gianni Puccini's I Sette Fratelli Cervi (1968) and Pietro Germi's comedy Alfredo, Alfredo (1972), starring Dustin Hoffman. Del Prete made a couple attempts to become popular outside of Italy. He had a good start in Joseph Losey's acclaimed The Assassination of Trotsky (1972), but his two subsequent international efforts in Peter Bogdanovich's Daisy Miller (1974) and At Long Last Love (1975), were box-office duds and Del Prete returned to performing almost exclusively in Italy.